docs: Loki 3.0 Release Notes

[JStickler]

What this PR does / why we need it:

Collects content from "next.md", RADS, and CHANGELOG into a draft for the next Release Notes.

[grafanabot]

This PR must be merged before a backport PR will be created.

[trevorwhitney]

FYI: 3.0 is released with partial release notes, we'll need to copy these over to the GH release when ready to go

[slim-bean]

I wonder if we should remove this, it just links to the configs?

[JStickler]

It wanted to call out the "clean up the campfire" work explicitly, since it was a lot of effort.

[grafanabot]

The backport to release-3.0.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-12508-to-release-3.0.x origin/release-3.0.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x 060b6c288f2b3fd70d20e35a5f555f787ff02b92

When the conflicts are resolved, stage and commit the changes:

git add . && git cherry-pick --continue

If you have the GitHub CLI installed:

# Push the branch to GitHub:
git push --set-upstream origin backport-12508-to-release-3.0.x
# Create the PR body template
PR_BODY=$(gh pr view 12508 --json body --template 'Backport 060b6c288f2b3fd70d20e35a5f555f787ff02b92 from #12508{{ "\n\n---\n\n" }}{{ index . "body" }}')
# Create the PR on GitHub
echo "${PR_BODY}" | gh pr create --title "chore: [release-3.0.x] docs: Loki 3.0 Release Notes" --body-file - --label "size/M" --label "type/docs" --label "product-approved" --label "backport" --base release-3.0.x --milestone release-3.0.x --web

Or, if you don't have the GitHub CLI installed (we recommend you install it!):

# Push the branch to GitHub:
git push --set-upstream origin backport-12508-to-release-3.0.x

# Create a pull request where the `base` branch is `release-3.0.x` and the `compare`/`head` branch is `backport-12508-to-release-3.0.x`.

# Remove the local backport branch
git switch main
git branch -D backport-12508-to-release-3.0.x

[Tenzer]

We are only in April, so I think this should have been 2024-04-08?

[JStickler]

Yep that's a typo. There's a fix in #12533.